So many things can give you pain. Squeezing the fingers together, pressing the thumb too hard against the pointer finger, cupping your hands, fingers out of line, holding your hand to flat and rigid, flexing the wrist the wrong way, pressing the hand down too hard before you get to the catch. I don't think any one can correct the problem without seeing what you are doing wrong. It may be how you finish the stroke. All the things I mention are involved with hand position. It may be something you are doing in the recovery mode. Too much tension on recovery..... It may have something to do with your breathing. ????